Posted
by
Zonk
on Saturday September 10, 2005 @12:49AM
from the i'd-like-you-to-meet-a-giant-space-rock dept.

ewhac writes "The San Francisco Chronicle is reporting that the new Trans-Neptunian objects mentioned in the press earlier this year are being formally announced this week at a planetary conference in Cambridge, England. Bearing the extremely temporary names 'Xena,' 'Santa,' and 'Easterbunny,' the new objects are quite interesting in their own right (Santa is cigar-shaped, rotates end-over-end every four hours, and has a 60-mile-diameter moon). However, even more interesting is the intrigue behind the press conferences revealing Xena earlier this year. It seems that, using the astronomers' own observation logs (publicly available over the Web) and some key details inadvertently revealed in earlier announcements, someone was planning on 'discovering' the objects first and claiming credit. This was why the scientists 'pre-announced' the existence of Xena back in July, to establish priority. The conference in Cambridge represents the first formal, scientific disclosure of the objects."

I don't care much for the whole pre-announcing subplot here, but I think that making this kind of discovery is great.

It's better than suspending tadpoles in a ziplock bag for an hour and then spending three days worrying about destroying all the evidence on re-entry.

So the question is what is the composition of these bodies? Are they rich in any materials that we may find useful to harvest in the future? If so, how can we get up there and bring those materials back?

Are they rich in any materials that we may find useful to harvest in the future? If so, how can we get up there and bring those materials back?

These objects are in the Kuiper Belt... They are BEYOND THE ORBIT OF NEPTUNE.

I submit to you that there are no materials valuable enough to justify the energy required to move that much mass to the inner solar system, in any reasonable amount of time. For Christ's sake, we're barely at the point where we can get to Mars and back, let along move any significant amoun

"I submit to you that there are no materials valuable enough to justify the energy required to move that much mass to the inner solar system, in any reasonable amount of time."I believe you are making a point that is true today, but 10, 15,100 years from now, who knows? With better technology, you just can't tell.

Mining is all about return vs. investment, and with as much as some things increase in price you can not really predict when it will become profitable to mine something even that far out.

Well, unless we find a vastly more efficent and cheap way to get objects into Earth orbit and then beyond, then no. It's simply a lot cheaper to mine things on Earth. Maybe if/when we start to run out of certain materials, it might make sense. But even then we would go to the asteroids, not comets. Asteroids are both closer *and* richer in metals. Comets are mostly ices, after all.

So I'd saying having any expectations of mining these objects is sort of a stretch right now.

Except that you'd have to extract the water from the methane and ammonia first. Not to mention the enormous difficulty in hauling that much water across the entire solar system. It's something we're utterly incapable of now and will be for the foreseeable future, so it's not really worth counting on.

Except that you'd have to extract the water from the methane and ammonia first. Not to mention the enormous difficulty in hauling that much water across the entire solar system. It's something we're utterly incapable of now and will be for the foreseeable future, so it's not really worth counting on.

"Hauling stuff across the solar system" is much easier than hauling it up to orbit (as long as you don't have any passengers). Space probes have been travelling to the outer planets for the last 30 years. You

Actually, quite wrong. It takes about 10 times as much energy to haul something from Pluto's orbit to Mars's orbit as it does to haul it off of the Earth. Moving something from the Kuiper Belt to the Moon would be even more costly since Earth is nearer the Sun. Even with gravity assists to lose momentum (not gain it; you're going *in*, here), it's unlikely that it would be cheaper, especially since I can arrange for gravity assists leaving from the Earth as well as leaving from the outer solar system.T

It's not the amount of energy, it's how expensive. You need a do-or-die blast to get into Earth orbit. If you're not fighting our gravity or air resistance, you can use slower and more efficient methods and take years rather than minutes. You can use nuclear power (a no-no for Earth launches), you can even use solar. From the payload you might use rocky matter in massdriver or volatiles in a rocket.

Energy=cost, pretty much. Fuel is fuel, not matter how quickly or slowly you use it. And for TNOs you have to HAUL it out there to use it. Which costs... fuel."Closer orbits are faster. p=mv."Apologies, I was not specific. *Angular* momentum. I had rather thought you knew that, though, since linear momentum is totally irrelevent here as is abundantly obvious. Apparently not. And while I didn't particlarly mean to patronize you, it's becoming clear that you don't have a very good grasp of orbital mecha

Yeah, and in 10, 15, 100 more years, monkeys might fly out of my butt. No, really--they might.The argument that "this may become economical in the future, given better technology" is a nonsense argument because it's a truism, but it's a useless truism. We don't know what the future will hold, so any statement with "may" in it is perfectly valid, logically. But at the same time, making the statement is totally pointless because it merely states the obvious: that the future is unknowable.

Getting into orbit is relatively hard. Once you are there, there are earth-orbiting asteroids. Capture one and build a solar sail. Your solar sail vessel can then get to the edge of the solar system. The next step is rather trickier. Use the solar sail to apply orbital drag on the target object and drop it back towards the sun.

Of course, this same technique could be used on objects closer to us, so there's not much incentive to go that far.

RE: "that is true today, but 10, 15,100 years from now..."When a significant majority in one of the advanced space faring states believes the earth is no older than 7,000 years. where do you expect the financing of the basic science necessary to even contemplate the tasks you outline? Scientific reasoning and knowledge is being devalued continuously for more faith based "logic". Moreover, for the immediate future those following the latter, easier path will live the more comfortable life.

I personally do not participate in moderation because of its many abuses. Including the "overrated" tag that should never be allowed to be used as an initial moderation IMNSHO. Of course the broken mod system is well known.

First let me explain the delay. I was composing a reply, that may have been harsher than this response when my keyboard lost its ability to render a significant set of characters needed to respond. I had spilled coffee earlier, after a trip where I purchased a new keyboard and other items, again my response was halted when a momentary power drop dimmed the lights and rebooted all our computers. Afterwards, I just had other activities. So that's the reason for my retarded answering.I noticed several poin

You make a great deal of assumptions about my background in your post., assumptions that are in fact quite wrong. Let me then also say that you further make assumptions about my argument that are very wrong. My background is virtually irrelevant, but let me assure you that an appointment to Imperial College London in 1990 , S1 levels in Physics, Math and Chemistry and a full research fellowship are part of my past. Further I have been a database developer on more than a small number of medical research proj

FTA: "In the case of the new planet, however, we know that even if it is extremely reflective (like fresh snow, for example) it still cannot be as bright as it is unless it is bigger than Pluto. Thus while we don't know for certain the precise size, we know for certain that it is bigger than Pluto."

How? I don't understand this logic here. What am I missing?

If one person holds a dirty 20 (cm) mirror in pitch darkness about a 100 meters away from me, another person holds a shiny 10 (cm) mirror about 200

Try putting them 1 and 2 km away, and you will see what the whole thing is about: they will only be points of light, so brightness and distance (and for a planet mass gained by observing multibody interactions) will be the only ways to determine the size.

Ok. Well, then you are saying that the planet is a clean 10 (cm) mirror and pluto is a dirty 10 (cm) mirror. Right? You still cannot infer that a 10 (cm) mirror is bigger than a 10 (cm) mirror - since at that _vast_ relative distance they still appear to be the same size to us, only one's brighter than the other.

Reflectivity !-> Size

in other words, convince me a white dwarf star (the size of earth) 50 million light years away is bigger than a Gas Giant planet some 20 million light years away. Gra

Bigger objects reflect more light than smaller objects made of the same substance.

Objects appear dimmer the further away from the viewer they are.

The reflectivity of Pluto is known (reflects 60% of sunlight).

The size of Pluto is known.

No substance known reflects 100% of the light that hits it.

The orbit of the new object is known.

From this we can calculate the brightness of a perfect mirror the size of Pluto if it were in the new object's orbit.

From observations we know that the object is almost as bright as a Pluto-sized mirror would be at this distance.

Thus, the smallest the object can be is 97% the size of Pluto. Since the object cannot be a perfect mirror, it is bigger than Pluto.

Likewise, the reflectivity of other substances can be tried. If the object is made of snow (90% reflectivity) it will be 2% larger Pluto, and if the object has the same composition as Pluto it will be 25% larger than Pluto.

> Thus, the smallest the object can be is 97% the size of Pluto. Since the object cannot be a perfect mirror, it is bigger than Pluto.

97%? How did you reach that calculation?

> Likewise, the reflectivity of other substances can be tried. If the object is made of snow (90% reflectivity) it will be 2% larger Pluto, and if the object has the same composition as Pluto it will be 25% larger than Pluto.

Albedo (reflectivity) can be between 0 (no light is reflected) and 1 (all light is reflected). Pluto's albedo is 0.6.

So, if 2003 UB313 has the same reflectivity as Pluto, it would be about 3000 diameter. If it is somewhat brighter (albedo = 0.8) its diameter would still be 2600 km. If p = 1.0 it would be about the size of Pluto. In the unlikely case that it is very dark, it would be far larger t

Place a marble which is polished clear white, 1 inch in diameter, and 2 feet behind a brown marble 1.1 inches in diameter, and just stand 30 ft across a dark room and shine a light at it. Tell me which one reflects more light back.

The amount of light reflected is proportional to the product of the diameter of the marble and its reflectivity, and inversely proportional to the square of the distance from the light source. The amount of light received by the observer is proportiona

Indeed. My original hypothesis that you were a broken google record was correct.

Looks like my original hypothesis that you are a troll was also correct.

Pluto's radius is not well known. JPL's value of 1137 is given with an error of +/-8, almost one percent. Now extrapolate that estimate while estimating the albedo of said discovered planet, and drawing _conclusions_ that it is bigger.

The lower bound for the size of 2003 UB313 isn't determined by the albedo of Pluto.
Furthermore, a variance in Pluto

If one person holds a dirty 20 (cm) mirror in pitch darkness about a 100 meters away from me, another person holds a shiny 10 (cm) mirror about 200 meters away from me, and I shine a _powerful_ flashlight at them, I see the smaller mirror is brighter, yet it's NOT bigger, and both appear the same size relative to me.

At the distances the planets are from us, both objects look like specks. They will probably be larger on something like Gemini but there won't be a difference in sizes due to the distance.

> In addition, we already know how far away the objects are due to measurements of it's position...

Indeed. That's a given (I suppose). I think you even mentioned "estimates" (by accident or not). What I meant to convey by my mirror analogy is a direct translation of what the article is stating. It makes the following logical equivalence (in mathematically discrete terms):

Reflectivity [is logically equivalent to] Size

...and I disagree (or fail to understand) that statement in the article.

So the question is what is the composition of these bodies? Are they rich in any materials that we may find useful to harvest in the future? If so, how can we get up there and bring those materials back?

Better question is how do we go out there and utilize those materials in-situ? I remember an idea where a shaft would be drilled in an asteroid then a big mirror would be used to melt the asteroid as it spins so it becomes a molten blob filled with gas which expands like a balloon. Once it cools it would b

No, I am not even an astronomer.
But, stealing research results happens. It may happen unwittingly over a cup of coffee or it may be someone actively snooping.
Anyhow, results published by the 'wrong team' may lead to less or even no funding. Several years of funding may dissappear in a puff and no editor would ever re-publish your 'scientific news'.

I don't have access to the necessary data and my training in this area is thin, but one possibility that springs to mind is that the object has too much angular momentum. I'm sure every slashdotter knows that the Earth is slightly flattened by its rotation. As you add more angular momentum you normally expect the object to just flatten more and more as it spins faster and faster. It turns out that after a certain point the body will be more stable as a tumbling elongated shape than a fast spinning disc. Con

I imagine what they mean is that the diameter of the new object is bigger than pluto's diameter or something along those lines.
I don't know why something in a cigar shape couldn't be bigger than pluto. Its like asking how could a cigar be bigger than a marble. It just is.

As the article points out, this brings the question Pluto's "planet" status to the fore. It never really fit in with the other 8 planets to begin with (compostion, relation to the ecliptic, etc.), but now that both a larger Kuiper Belt Obeject and one with a moon have been discovered, the pure scientist in me hopes that it would be possible to push everyone back towards the idea that there are only 8 planets in our solar system.
Read the article. It's worth it just to see the term "plutinos" suggested as a common name for KBOs.

As the article points out, this brings the question Pluto's "planet" status to the fore.

Not particularly; we still don't have any more data to decide Pluto's status.

The best definition of "planet" I have seen is a body that orbits a star and is large enough to have assumed and retained a nearly spherical shape under its own gravity. According to that, Pluto is probably a planet, but we won't know until we get closer.

The conventional boundary is having enough mass to maintain a (near-) spherical shape, which Pluto certainly does. I say it's a planet, and so are any of these large enough to be spheres. Of course then we have to admit Ceres and Vesta, but that should have been done a long time ago, IMO.

I remember just a year or two ago, there was a planet discovered in the Kuiper Belt, given a name starting with a 'Q' if I recall correctly. Then the media started hyping a 10th planet just this year with a new KBO, forgetting the previous discovery.

The problem is that so many of these new KBOs could be larger than Pluto once we find them, even though they might not fit other criteria we'd been using for planetary designation. It actually makes more sense to downgrade Pluto to a simple KBO, and create a more rigid definition of a major planet.

I watched the discussions about the "hacking incident" on the minor planets mailinglist...They discovered the first object, calculated the trajectory and didnt publish it for nearly a year.If they dont want to get their discovery "stolen", they shouldnt monopolize observation time by not publishing.

And also, there is NO proof that those proposed methods were used. The re-discovery by the other team was absolutely legit, and they just wet their pants because they feared they would lose the fame for all those

No. Really. They aren't even real names. They are just the code names the discoverers have been using. (2003UB313 doesn't really trip off the tongue.) For Sedna, they used the code name "Flying Dutchman", and nobody remembers that.

Since Xena: Warrior Princess is a trademark of Universal TV Distribution Holdings LLC
and a copyright of Universal Television Enterprises LLLP, could they potentially sue for usage of a refernce to Xena?
I realize this is not going to happen, just curious as to the legal possibilities.

Thing is, Newtonian mechanics aren't the ONLY rules they follow. They also follow the rules of chemistry, solid state physics and thermodynamics. And it is these things (and others) which appear to have the potential to lead to some very [caltech.edu] very [space.com] weird things indeed. That's why people think these things are exciting.